Hybrid organic-inorganic metal halide perovskites, which include a wide range of organic cations and inorganic anions, are a class of crystalline materials that can have structural tunability. By choosing appropriate organic and inorganic components, the crystallographic structures can be controlled with the inorganic metal halide octahedrons forming various crystal structures surrounded by organic moieties (see, e.g., Mitzi, D. B. Journal of the Chemical Society-Dalton Transactions, 1-12 (2001); Gonzalez-Carrero, S., et al. Part Part Syst Char 32, 709-720 (2015); and Saparov, B. et al. Chem Rev 116, 4558-4596 (2016)). The integration of useful functionalities of both organic and inorganic portions within a single bulk assembly can enable these materials to possess unique electronic, magnetic, and optical properties. In recent years, the use of hybrid organic-inorganic metal halide perovskites in optoelectronic devices has been explored, including photovoltaic cells (PVs), light emitting diodes (LEDs), photodetectors, and optically pumped lasers (see, e.g., Kojima, A., et al. J Am Chem Soc 131, 6050 (2009); Tan, Z. K. et al. Nat Nanotechnol 9, 687-692 (2014); Ling, Y. C. et al. Adv Mater 28, 305-311 (2016); Dou, L. T. et al. Nat Commun 5 (2014); Xing, G. C. et al. Nature Materials 13, 476-480 (2014); and Stranks, S. D. et al. Nat Nanotechnol 10, 391-402 (2015).
The chemistry of metal halide perovskites can enable band gap control and color tuning. Highly luminescent 2D, quasi-2D, and 3D perovskites have been obtained with tunable, narrow emissions, by controlling chemical composition and quantum confinement (see, e.g., Protesescu, L. et al. Nano Lett 15, 3692-3696 (2015); Sichert, J. A. et al. Nano Lett 15, 6521-6527 (2015); Dou, L. T. et al. Science 349, 1518-1521 (2015); and Yuan, Z. et al. Chem Commun 52, 3887-3890 (2016)). Broadband emissions across the entire visible spectrum have also been realized in corrugated-2D and 1D perovskites (see, e.g., Dohner, E. R., et al. J Am Chem Soc 136, 1718-1721 (2014); Dohner, E. R., et al. J Am Chem Soc 136, 13154-13157 (2014); Hu, T. et al. J Phys Chem Lett 7, 2258-2263 (2016); Cortecchia, D. et al. arXiv 1603.01284 (2016)). Color tunability and high photoluminescence quantum efficiency (PLQE) can make metal halide perovskites desirable light-emitting materials. The research regarding hybrid organic-inorganic metal halide perovskites, however, has focused on 3D and 2D structures instead of 1D and 0D structures (see, e.g., Takeoka, Y., et al. Chem Lett 34, 602-603 (2005)).
Also, most high performance perovskites developed to date contain lead, which is a toxic heavy metal. Therefore, the use of lead can, in some instances, present a challenge for the potential adoption of these materials because all lead-free metal halide perovskites discovered to date, such as tin and bismuth perovskites, have shown low PLQEs (see, e.g., Noel, N. K. et al. Energ Environ Sci 7, 3061-3068 (2014); Hao, F., et al. Nat Photonics 8, 489-494 (2014); Park, B. W. et al. Adv Mater 27, 6806 (2015); Jellicoe, T. C. et al. J Am Chem Soc 138, 2941-2944 (2016); and Peedikakkandy, L. et al. Rsc Advances 6, 19857-19860 (2016). For example, the 0D perovskite (CH3NH3)4PbI6.2H2O is non-emissive, and has low stability under ambient conditions (Takeoka, Y., et al. Chem Lett 34, 602-603 (2005)).
Therefore, perovskite materials having structures other than 1D, 2D or 3D, and are stable, efficient, color tunable, lead free, and/or have a relatively high PLQE are desirable.